Renewal of signaled shuttle box avoidance in rats

Abstract

Five experiments with rats explored the renewal of acquired then extinguished avoidance behavior. Rats were individually trained to avoid signaled electric shock by crossing the midline of a shuttle box. Each midline crossing response stopped the auditory signal and cancelled the shock scheduled at the end of the signal. The midline crossing response was then extinguished by presenting the signal without the electric shock. Avoidance behavior was renewed when the rats were tested outside the extinction context. The rats were treated in 1 of 3 background contexts (A, B, and C) differing in multi-modal cues. The renewal of avoidance behavior was observed when the combination of acquisition, extinction, and test contexts was ABA, ABC, or AAB. The renewal amount was equivalent across the 3 paradigms, indicating that a critical factor in avoidance renewal is a release from the extinction context rather than a return to the acquisition context. The direct context–shock association seems to play a small role even in ABA renewal because repeated extra exposures to the acquisition context, which must have weakened the putative context–shock association, had little effect on the amount of ABA renewal.